A limiting factor in the performance of an internal combustion engine is the amount of combustion air that can be delivered to the intake manifold for combustion in the engine cylinders. Atmospheric pressure is often inadequate to supply the required amount of air for proper operation of an engine.
An internal combustion engine, therefore, may include one or more turbochargers for compressing air to be supplied to one or more combustion chambers within corresponding combustion cylinders. Each turbocharger typically includes a turbine driven by exhaust gases of the engine and a compressor driven by the turbine. The compressor receives the air to be compressed and supplies the air to the combustion chamber. It is also known to use turbochargers to compress gaseous fuels, and to compress a fluid stream mixture of combustion air and fuel.
A conventional multi-stage turbocharger includes a turbine section and two or more compressor sections. A common shaft interconnects the turbine wheel of the turbine section with compressor wheels in the compressor sections. Ambient air to be used for combustion in the internal combustion engine is brought into an inlet for the first compressor section. The air is compressed by the first compressor wheel, and passes from the first compressor section through a first compressor section outlet to the inlet of the second compressor section, for further compression. An interstage duct is used to conduct the compressed air from the first compressor section outlet to the inlet of the second compressor section. The out flow from the second compressor section exits the turbocharger at the second compressor section outlet, and is directed to the inlet manifold of the internal combustion engine.
One of the problems associated with the use of turbochargers is the build up of heat in the compressed air. Heat reduction has been accomplished through the use of so called "interstage coolers" between the compressor stages of a multistage turbocharger and/or so-called "aftercoolers" between the second or last compressor outlet and the intake manifold. Known interstage coolers and aftercoolers have included external units to which the compressed air is ducted for cooling therein. Ducting to and from interstage coolers and aftercoolers can be complex and expensive to manufacture.
Another problem associated with the use of turbochargers is the complex housing or scroll which surrounds the compressor wheels, and the complex interstage duct used to connect compressors of a multi-stage turbocharger. Manufacture of these components is complex and difficult, and adds significantly to the cost of providing a turbocharger.
It is known from U.S. Pat. No. 5,528,902 to provide a support housing to which exhaust gas turbochargers are fastened. The housing encloses a hollow space which receives the turbines of the exhaust gas turbocharger, while the compressors are situated outside the hollow space. The turbines include turbine housings having spiral ducts for the flow of exhaust gases there through.
The present invention is directed to overcoming one or more of the problems set forth above.